Small Gas Engine Parts Identification Four-Stroke Cycle By Dave Wilson Information Technology and Communication Services ITCS Instructional Materials University of Illinois Urbana-Champaign Copyright ® 2010 University of Illinois Board of Trustees

Introduction Previous Slide Contents Next Slide To view individual carburetor parts, a table of contents with links is provided in frames 4 and 5. To view the individual parts, the user may click on the part name from the table of contents, and the link will navigate to the part. Clicking the Contents button will return the user to the table of contents. Clicking Quit will return to the Master Navigation slide. Previous Slide Contents Next Slide Click on the buttons on each page for easy navigation through the slides. Quit 2

Introduction Knowing the parts of an engine is one of the first steps to learning engine repair and maintenance. Repair technicians gain confidence in themselves, and their customers gain confidence in them when they identify parts using the jargon of the industry. Another function of learning engine parts is to communicate with customers, other technicians, parts providers, and manufacturers using terms that are equally understood. Using universally understood terms promotes efficiency within the industry. It is important to understand the relationship between engine parts to gain an understanding of how an engine works. Additionally, understanding how an engine works is key to diagnosing an engine problem. Diagnostic skills are a learned talent, and it requires practice to improve their application with efficient repair and maintenance of small gas engines.

Table of Contents Quit Slide Slide Oil ring with expander …………… 27 Piston pin or wrist pin ……………. Piston pin locks …………………... Connecting rod …………………… Connecting rod screws with piston assembly …………………..……………… Exhaust valve …………………….. Intake valve ………………………. Valve spring ………………………. Valve retainer …………………….. Valve tappet ………………………. Camshaft ………………………….. Intake manifold …………………… Intake manifold gasket …………... Rewind starter housing ………….. Starter rope with starter housing ……… Starter rope grip ………………….. Mechanical governor link with spring Governor control lever …………… Governor shaft (crank) with retainer . Oil slinger/governor ……………… 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Cylinder assembly with head gasket … Oil seal (magneto end).. ………….. Engine sump or crankcase cover .. Cylinder head with head bolts …………. Head gasket ……………………….. Breather gasket …………………… Breather assembly ………………... Breather tube ……………………… Crankcase gasket ………………… Cylinder head bolts ………………. Oil drain plug ………………………. Crankshaft …………………………. Oil seal (PTO end) ………………... Crankcase cover screw ………….. Flywheel ……………………………. Flywheel key ………………………. Piston ………………………………. Top compression ring with piston …… Center compression ring and piston . 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Table of Contents Quit Slide Slide Oil dipper …………………………… Dipstick with dipstick tube ………………... Magneto armature ………………… Spark plug …………………………. Stop wire attached to flywheel brake …… Brake assembly …………………… Air filter …………..…………………. Flywheel cup with nut …………………… Blower housing (shroud) …………. Cylinder shield …………………….. Breather passage cover with gasket . Timing gear ………………………… Muffler with mounting screws and lock …. Muffler guard ………………………. Muffler deflector …………………… O-ring seal …………………………. Fuel tank cap ………………………. 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 Air cleaner base …………………. Air cleaner cover ………………… Fuel line with hose clamps ……………. Fuel tank with cap ……………………… Control bracket ………………….. Carburetor ……………………….. Push rod …………………………. Flywheel nut ……………………... Cover, overhead valve engine … Overhead valve engine head ….. Rewind guard ……………………. Exhaust gasket ………………….. 64 65 66 67 68 69 70 71 72 73 74 75 76 Quit

Cylinder assembly with head gasket

Oil seal (magneto end)

Engine sump or crankcase cover

Cylinder head with head bolts

(cylinder head gasket)

Breather gasket

Breather assembly

Breather tube

Crankcase gasket

Cylinder head bolts

Oil drain plug

Oil drain plug

Oil drain plug

Crankshaft

Oil seal (PTO end) PTO = Power Take Off

Crankcase cover screw

Flywheel

Flywheel key

Piston

Top compression ring with piston

Center compression ring and piston

Oil ring with expander

Piston pin or wrist pin

Piston pin locks

Connecting rod

Connecting rod screws with piston assembly

Exhaust valve

Intake valve

Valve spring

Valve retainer

Valve tappet

Camshaft

Intake manifold

Intake gasket

Rewind starter housing

Starter rope with starter housing

Starter rope grip

Mechanical governor link with spring

Governor control lever

Governor shaft (crank) with retainer

Oil slinger/governor

Oil dipper

Dipstick with dipstick tube

Magneto armature

Spark plug

Stop wire attached to flywheel brake

Brake assembly

Air filter

Flywheel cup with nut

Blower housing (shroud)

Cylinder shield

Breather passage cover with gasket

Timing gear

Muffler with mounting screws and lock

Muffler guard

Muffler deflector

O-ring seal

Fuel tank cap

Air cleaner base

Air cleaner cover

Fuel line with hose clamps

Fuel tank with cap

Control bracket

Carburetor

Push rod

Push rod

Flywheel nut

Cover, overhead valve engine

Overhead valve engine head

Rewind guard

Exhaust gasket

University of Illinois End of show Quit This material was prepared by Dave Wilson, Information Technology and Communication Services, and reviewed by Dr. Joe Harper, Department of Agricultural and Biological Engineering, College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana-Champaign. Photographs by the author. University of Illinois 1917 South Wright Street Champaign, IL 61820 (800) 345-6087 http://im.itcs.illinois.edu/ J-BA